Last month we discovered that our soakaway was broken, so decided to construct a reed-bed system to handle the grey water from our kitchen and outside sink. The idea is that eventually, the cleaned water from this will feed a pond, somewhere else in the garden.
Preparation
First, we got a Bulgarian trench-digger to dig a trench from the existing soak-away to where we thought the reed-bed might go. With some help from another friend we managed to fill in the soak-away, build a manhole into the pit so we can clean the drain if needed, and installed the drainage pipes that he kindly donated. As our land only slopes very gently, we had to try hard to get the minimum slope that we could on the pipes. Even so, our reed bed has had to be sunk into the ground so we can get the water to flow in at the top of the bed.
Designing the Reed-bed
We thought hard about how large to make our reed-bed. We did some calculations based on our estimated water throughput of about 11 litres a day, and decided that a 1m² bed would be sufficient. Then we realised that our water usage is so low, that we might not be actually producing enough water to keep the planned pond topped up in the heat of summer. We decided then to make the bed large enough to handle the additional flow of 75 litres from the washing machine, and to move the washing machine into the kitchen, instead of the outbuilding where it currently lives. So now we’ve ended up with a nearly 2m² bed.
We didn’t want to make a cement-contained reed bed, and we can’t get pond liner locally (at least not cheaply enough!) so we improvised with roofing felt liner to smooth out any sharp stones, a base layer of sieved sand, thick plastic on top of that and a thick layer of sieved sand to protect the plastic from the sharp gravel.
The Build
We surrounded the inlet pipe with large rocks so the water has to flow around them and won’t just flow along the top of the bed and out of the outlet pipe, so hopefully it will all get filtered by the reeds. The inlet pipe is above water level so we covered it with mesh so stop frogs etc making a home up there. Initially, we wanted to have the reed-bed filled completely with gravel so that we don’t get problems with midges and mosquitoes, but we may re-consider this when we build the larger pond next year. We will provide a small sunken section so that the wildlife in the garden can get access to water for drinking.
When we filled it with water we had some initial teething problems with getting the water levels right, as we hadn’t appreciated the extent to which the reed-bed slows down the drainage of water, so we needed to drop the outlet pipe to allow the system to partially fill before it could drain away, and left 2 inches of plastic sheeting above the gravel for when the washing machine is used as the water won’t drain out quick enough. Once we’d got that right we sealed the liner to the inlet and outlet pipes with electrical tape, installed the outlet pipe and filled it with gravel.
We got permission to gather some reeds from a local fishing lake in the village, and also gathered some plants from above the water-line to give a more natural, blended look to the finished reed-bed. We got a load of mud with them too, so hopefully there will be lots of interesting things growing in the mud that will help populate the reed-bed with some extra life! We edged the sides with limestone rocks from the garden and hey presto a reed bed. All we’ve had to buy was the roofing felt, liner, gravel and sand, total cost for materials about 35 lev.
I’m impressed!! Nice work!
Impressed with the reed bed. We made a pond and lined it with a butyl liner And planted some reeds on the edge of the pond. A couple of years later the pond level started going down. The viscious bamboo-like roots of the reeds had travelled under the liner and come up through it creating loads of holes! It was a helluva job to fix the problem.
I’m sure you’ll be ok but just beware of reed roots